CVE-2026-12067: vulnerability in Gen Digital Avast Antivirus, Avast One, Avast…
AvastSvc denial of service via unhandled JsonCpp exceptions in native message handlers
Published
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0Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Track
Missing exception handlers in AvastSvc native message dispatcher (ashServ.dll) on Windows allow a local, unprivileged attacker to crash the service by sending specially crafted JSON messages.
The vulnerability spans multiple handler pathways in the RPC-based native message protocol:
* Log_NmSvc.message handler: converts JSON fields to strings without type validation and without exception boundaries.
* OpenInSz_NmSvc handler: converts URL and origin fields to strings without type checking, exposing an exception.
* OpenInSz_NmSvc.profile handler: converts the profile field to an integer without validation.
In all three cases, the exceptions are not caught by action-specific handlers and propagate up the dispatcher. The common root cause is the absence of try-catch blocks around JSON type conversions in the native message processing chain.
Affected products
Gen Digital · Avast Antivirus, Avast One, Avast Premium Security, Avast Ultimate, Avast Business SecurityGen Digital · AVG Antivirus Free, AVG Internet Security, AVG UltimateGen Digital · Norton Antivirus Plus, Norton 360 Standard, Norton 360 Deluxe, Norton 360 AdvancedRelated CVEs — Gen Digital Avast Antivirus, Avast One, Avast…
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